From 2aaf94484ebfd7a19a22b490b42925ee7d916795 Mon Sep 17 00:00:00 2001
From: Adrian Roos <roosa@google.com>
Date: Tue, 20 Nov 2018 16:57:33 +0100
Subject: [PATCH] Keyguard: Fix leaking fingerprint registration

Fixes an issue where the fingerprint registration could leak for the following
sequence of requests:

- shouldListen becomes true
- updateListening (STOPPED -> RUNNING)
- shouldListen becomes false
- updateListening (RUNNING -> CANCELLING)
- shouldListen becomes true
- updateListening (CANCELLING -> RESTARTING)
- shouldListen becomes false
- updateListening (nop, because RESTARTING is not considered a running state)
- handleFingerprintError(reason=CANCELLED) wrongly restarts listening

Bug: 119813074
Test: Verify fingerprint unlocking still works. Verify fingerprint listening does not get stuck after unlocking via bouncer.
Change-Id: Ibd1bf3a161164586466d2b1d965e53a648c7038b
---
 .../com/android/keyguard/KeyguardUpdateMonitor.java | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/packages/SystemUI/src/com/android/keyguard/KeyguardUpdateMonitor.java b/packages/SystemUI/src/com/android/keyguard/KeyguardUpdateMonitor.java
index 6b0a7a95bba33..b55aa5c8897d2 100644
--- a/packages/SystemUI/src/com/android/keyguard/KeyguardUpdateMonitor.java
+++ b/packages/SystemUI/src/com/android/keyguard/KeyguardUpdateMonitor.java
@@ -1531,10 +1531,11 @@ public class KeyguardUpdateMonitor implements TrustManager.TrustListener {
         }
         mHandler.removeCallbacks(mRetryFingerprintAuthentication);
         boolean shouldListenForFingerprint = shouldListenForFingerprint();
-        if (mFingerprintRunningState == BIOMETRIC_STATE_RUNNING && !shouldListenForFingerprint) {
+        boolean runningOrRestarting = mFingerprintRunningState == BIOMETRIC_STATE_RUNNING
+                || mFingerprintRunningState == BIOMETRIC_STATE_CANCELLING_RESTARTING;
+        if (runningOrRestarting && !shouldListenForFingerprint) {
             stopListeningForFingerprint();
-        } else if (mFingerprintRunningState != BIOMETRIC_STATE_RUNNING
-                && shouldListenForFingerprint) {
+        } else if (!runningOrRestarting && shouldListenForFingerprint) {
             startListeningForFingerprint();
         }
     }
@@ -1589,6 +1590,10 @@ public class KeyguardUpdateMonitor implements TrustManager.TrustListener {
             setFingerprintRunningState(BIOMETRIC_STATE_CANCELLING_RESTARTING);
             return;
         }
+        if (mFingerprintRunningState == BIOMETRIC_STATE_CANCELLING_RESTARTING) {
+            // Waiting for restart via handleFingerprintError().
+            return;
+        }
         if (DEBUG) Log.v(TAG, "startListeningForFingerprint()");
         int userId = ActivityManager.getCurrentUser();
         if (isUnlockWithFingerprintPossible(userId)) {
@@ -2418,6 +2423,8 @@ public class KeyguardUpdateMonitor implements TrustManager.TrustListener {
                     + getStrongAuthTracker().hasUserAuthenticatedSinceBoot());
             pw.println("    disabled(DPM)=" + isFingerprintDisabled(userId));
             pw.println("    possible=" + isUnlockWithFingerprintPossible(userId));
+            pw.println("    listening: actual=" + mFingerprintRunningState
+                    + " expected=" + (shouldListenForFingerprint() ? 1 : 0));
             pw.println("    strongAuthFlags=" + Integer.toHexString(strongAuthFlags));
             pw.println("    trustManaged=" + getUserTrustIsManaged(userId));
         }